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Sexual Hormone Binding Globulin

Meaning

A glycoprotein synthesized primarily by the liver that circulates in the bloodstream and binds with high affinity to sex steroid hormones, specifically testosterone, dihydrotestosterone (DHT), and estradiol. SHBG acts as a transport protein, regulating the bioavailability of these hormones by sequestering them into a bound, biologically inactive state. Only the fraction of hormones not bound to SHBG, known as the “free” fraction, is generally available to diffuse into target tissues and exert biological effects. Clinical measurement of SHBG is essential for accurately assessing an individual’s true hormonal status.